- ‘It Had Gotten Worse Over the Years’: Marko Hietala Reveals Why He Really Left Nightwish, Opens on ‘Regret’ He Felt About It  Ultimate Guitar
- MARKO HIETALA On His Decision To Quit NIGHTWISH: ‘I Was Regretting It Already When I Was Leaving’Â Â BLABBERMOUTH.NET
- MARKO HIETALA Talks Living With ADHD – “It’s A Relief To Know That There Are Things In Your History And In Yourself That You Just Cannot Help” (Video)Â Â bravewords.com
- MARKO HIETALA On Leaving NIGHTWISH: ‘I Was Regretting It Already When I Was Leaving’Â Â Metal Addicts
- Ex-NIGHTWISH Bassist/Vocalist MARKO HIETALA: ‘I’ve Had Some Really Bad Years Behind Me And It’s Time To Go Forward’Â Â BLABBERMOUTH.NET
